Russian Cosmonauts Prepare Dramatic Saw Repair on ISS Amid Worsening Air Leak; NASA Orders Brief “Safe Haven” Shelter for Crew Before Procedure Paused

Russian Cosmonauts Prepare to Saw ISS Module in Air Leak Crisis; NASA Orders Brief Evacuation Shelter for Crew | Latest Updates

HOUSTON, Texas – A long-running air leak in the Russian segment of the International Space Station escalated Friday, prompting Russian cosmonauts to plan an invasive repair involving sawing into the structure — a move that briefly triggered NASA to place five astronauts in evacuation-ready “safe haven” mode inside a docked SpaceX Crew Dragon spacecraft.

The incident, which unfolded on June 5, 2026, highlighted ongoing tensions and coordination challenges between NASA and Roscosmos over the aging station’s structural integrity. No one was evacuated, and the crew has since returned to normal operations after Roscosmos paused the high-risk repair for further assessment.

The leak originates in the PrK transfer tunnel (also called a vestibule or transfer chamber) attached to the Russian Zvezda Service Module. First detected in 2019, it stems from microscopic structural cracks in the module’s metal. Russian crews have spent years hunting for the exact sources using dust accumulation tests, applying specialized sealant (Germetall-1), and periodically isolating the area. While patches have temporarily slowed the leak at times — dropping it to near-zero in early 2026 — it has repeatedly returned. By early May 2026, the rate was roughly one pound of air per day; it worsened again this week, prompting Roscosmos to greenlight a more aggressive fix.

On Friday morning, two Russian cosmonauts — station commander Sergey Kud-Sverchkov and flight engineer Sergei Mikayev — prepared to use a saw to break into an enclosed area of the PrK to directly access and repair the crack. NASA officials expressed concerns over the elevated risk of the procedure, which could potentially worsen the leak or compromise structural integrity.

At approximately 9:04 a.m. ET, NASA mission control in Houston directed the four members of Crew-12 (Commander Jessica Meir, Pilot Jack Hathaway, ESA astronaut Sophie Adenot, and Roscosmos cosmonaut Andrey Fedyaev) along with NASA astronaut Christopher Williams to enter the docked SpaceX Crew Dragon spacecraft, don their spacesuits, and prepare for possible emergency departure. The move was described as a standard precautionary “safe haven” protocol.

The Russian cosmonauts did not enter the Dragon and continued initial preparations, but Roscosmos ultimately paused the saw-based repair after taking additional measurements. NASA spokesperson Bethany Stevens confirmed the reversal roughly two hours later: “Given this development, NASA has instructed the crew members inside the Dragon spacecraft to end the safe haven procedures and return to planned operations aboard the International Space Station.”

Roscosmos stated that specialists detected the leaks during pressurization tests of the Zvezda module’s transfer chamber and are now analyzing data before proceeding. One of two identified leaks may have been sealed, but officials emphasized no immediate threat to the crew or station remains.

The seven-person crew (including additional Russian cosmonauts) is safe and continuing normal science and maintenance activities. The ISS, a joint U.S.-Russian-European-Canadian-Japanese project operational since 2000, is scheduled for controlled deorbit around 2030. Persistent issues with the Russian segment, including this leak, have drawn scrutiny from NASA’s Office of Inspector General as a top safety concern.

This marks the latest chapter in a multi-year saga. Past fixes have included sealants, temporary patches, and even external inspections during spacewalks. NASA has stressed that while the leak is manageable and poses no acute danger, it underscores the challenges of operating aging hardware in orbit.

As of Friday evening, June 5, 2026, no further repair timeline has been announced. Both agencies continue close coordination, and station operations remain nominal.

Russian Cosmonauts Prepare to Saw ISS Module in Air Leak Crisis; NASA Orders Brief Evacuation Shelter for Crew | Latest Updates

Worsening air leak in Russian Zvezda module forces dramatic repair plan involving sawing; NASA briefly shelters astronauts in SpaceX Dragon. Full timeline, crew details, and current status of the long-running ISS crisis as of June 5, 2026.

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